There are a number of instances in mammalian systems where nutritional factors apparently regulate the level of specific enzymes. For example, a number of enzymes involved in the biosynthesis of fat increase in concentration when rats are fed high carbohydrate-fat free diets. Two of these enzymes, glucose-6-PO4 dehydrogenase and 6-PO4 gluconate dehydrogenase are regulated such that the rate of synthesis is proportional to the dietary consumption of carbohydrate. In addition cyclic AMP decreases the rate of synthesis of glucose-6-PO4 dehydrogenase. These two enzymes will be model systems to study the mechanisms by which hormones and diet regulate the synthesis of lipogenic enzymes. Six-PO4 gluconate dehydrogenase induction is accompanied by an increase in its mRNA (Transcriptional level regulation) but glucose-6-PO4 dehydrogenase synthesis seems to be regulated at both the transcriptional and translational level. This research will use fractionated protein synthesizing systems to determine the mechanism of the translational regulation of glucose-6-PO4 dehydrogenase synthesis. The mRNA coding for the synthesis of this enzyme will be purified to facilitate these studies. A system of cultured hepatocytes will be used to determine which nutritional and hormonal factors regulate the synthesis of both dehydrogenases. Finally, these methods will be used to investigate mechanisms regulating the synthesis of these enzymes in adipose tissue.